Screw-swaging machine



(No Model.) 2 Sheets-Sheet It.

A. 0. LEWIS. Y No. 328,951. SGREW'SWAGING Oct. 27, 1885. li 1. y ray. 2

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" A. u. hflwlsi SCREW SWAGING MACHINE. No. 323,951. Patented Oct. 27, 1885.

ihviTnn STATES PATENT Grinch.

ALBERT G. LEWIS, OF BROOKLYN, NEW YORK.

SCREW-SWAGENG iViAGt-HNE.

EQPECIFICATION forming part of Letters Patent No, 328,951, dated October 2'7,1885

Application filed October 16, 1883. Renewed April 8, 1885. Serial No. 161,588. (No model.)

To aZZ whom it may concern:

Be it known that I, ALBERT O. Lnwrs, a citizen of the United States, residing in Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in the Method of and Machinery for Manufacturing Screws by the Process known as Swaging, ofwhich the following is a description in such full, clear, concise, and exact terms as to enable any one'skilled in the art to which my invention belongs, or with which it is most nearly connected, to make and use the same, reference being had to the accompanying drawings, making part of this specification, and to the letters and figures of reference marked thereon.

Figures 1, 2, 4, and 8 of said drawings are side iews of screw-blanks held between dies and undergoing manipulation therein before theyhave reached the thread-cutting grooves; and Figs. 3, 7, and 9 represent the same in position between the thread cutting dies. Fig. 5 is a longitudinal section through the dies when in the act of receiving the screwblank. Fig. 6 is a top view of the lower die, or bottom view of the uppei-di said dies being counterparts of each other. Fig. 10 is a longitudinal section through the dies, and represents the blank in three positions during the operation of reducing, threading, and pointing, and Fig. 11 is a bottom View of the upper die in .Fig. 10.

My invention consists, first, in a novel method of threading and pointing screws by the process known as swaging, second, in novel machinery for manufacturing drivescrews.

Screw-swaging machines are Well known. No detail description is therefore necessary of the general construction and operation of this machine, since the points of novelty constituting my invention are not in the general construction and operation of the ma chine, but in the manner of forming the dies and arranging them with reference to each other, so that they will produce a pointed drive screw or ratchet thread screw the maximum diameter of whose thread shall be equal, or nearly equal, to the eiamctcr of the shank above the thread when completed.

Similar letters of reference indicate corresponding parts in all the figures.

In the practice of my invention 1 construct two dies, a and b, each being a facsimile of the other, and consisting of three partsviz., the inclined surface 9, Figs. 5, 6, 10, and 11, the pointing rim or die h, and the threadinggrooves f, substantially in the relative positions shown. That is to say, the dies are so formed that a portion of the blank in approaching the threading grooves shall be caused to revolve between two inclined surfaces 9 g,- whereby that portion of said blank being acted upon by the said surfaces will be diminished in diameter and increased in length. Extending along the entire length of one side of the reducing and threading dies I make an inclined elevation or rim, h, into which the point of the screw is formed.

The threading-grooves f are all made to slope from the outside toward the inside of the diesthat is, from the head to the point of the screw-the grooves in the dies being exactly the reverse of the thread to be formed by them on the screw. By these means when the screw blank is revolved between the threading-dies the effect is to draw the metal of the blank into the angle formed between the inclined rims h h, which form the pointingdies. These last-mentioned dies work close upon each other and operate to point the screw at the same time and by the same operation that the blank is reduced and the thread swaged thereon and insure the point of each screw being exactly upon the line of its axis.

In prosecuting my improved method of swaging the points and threads of screws, I take the blank 0, Fig. 1, only a part of the entire length of which is included between the dies a b. As the dies move forward, that part of the blank which is included between the said dies rolling between the inclined surfaces 9 g, is diminished in transverse mass, and being correspondingly lengthened is forced into the pointing-dies h h, which dies slope from the front to the rear of the reducing and threading dies, to allow for the lengthening of the bolt during the process of reducing and swaging thethread thereon. (See Fig. 8.) As the dies continue their forward movement, that portion of the blank which has been reduced in diameter comes into connection with the threading-dies, whereby the thread of the screw is swaged thereon and the pointing finished, as hereinbefore described. (See Fig. 9.) The complete operation herein described is illustrated in all its stages in Figs. and 11.

During the process of swaging the threads, as is well known, the metal of the blanks, in being depressed to form the minimum diameter of the thread, fulls into the grooves of the die to form the maximum diameter of said thread, the thread upon the said dies being raised above and sunk below the plane surface of the dies. The result of this operation is to form a thread of larger diameter than the blank upon which it is swaged. This is illustrated by Fig. 7, in which the dotted lines represent the original diameter of the blank. It is therefore evident that if a blank of uniform diameter .be acted on by the threadingdies, and screw-threaded but a portion of its entire length, the resulting screw will be one in which the diameter of the thread will be larger than the diameter of the shank above the thread, as shown in Fig. 7. It is to obviate this difficulty that I first reduce the portion of the blank to be threaded to such an extent that the thread when formed shall be of a diameter equal to that of the shank of the bolt. (See Fig. 9.)

It is obvious that this part of my invention relates to all forms of threads. In the drawings, however, I have illustrated only that form of thread which belongs to a drivcscrew.

By the term drive'screw as used in this specification I mean a screw having a conical point whose diameter at the base thereof is equal to the diameter of the screw, and having a thread the section of which makes a right-angle triangle, the hypotenuse thereof sloping toward the point of the screwthat is, the base of the right-angle triangle being the top of the thread the altitude is the junction with the body of thescrew, and its hypotenuse the slope of the thread from the top toward the point of the screw.

Drive-screws such as I have above described have been heretofore made by cutting the aforesaid thread thereon with chasers or dies, and by forming the point either before or after cutting the thread; but this method of producing the screw makes it too expensive to compete with spikes in the construction of railroads, telegraph-lines, and so forth. To supply these screws at low cost is, therefore, one of the objects of my present invention.

Various modifications of the forms in which these screws may be made are illustrated in Figs. 2, 3, 4, 5, and 6 of the drawings, which several forms of taper may be produced by the corresponding modification of the reducing, pointing, and threading dies, it being evident that by giving a proper form to such dies a screw of any desired taper and point may be produced from a blank having either parallel or inclined sides. When such tapered screws are swaged, I prefer to use a rotary die, as, since the lower end of the screw is of smaller diameter than the upper, there would be a dragging movement of the blank at that point over the face of the dies if longitudinally-reciprocating dies were employed.

It will of course be understood that the dies I have here described are attached to suitable machinery, which communicates to them a reciprocating motion, as is the case with all machines of this description, said motion being applied to either the upper or lower or both ies.

Having thus described my invention, I claim- 1 1. In a screw-swaging machine, the pair of dies described, having a reducing portion to reduce the diameter of that part of the blank which is to receive the thread, combined with a threading. portion, having the threadinggrooves-thereon partly sunk below and partly raised above the rear surface of the reducing portion for the purpose of forming a bolt in which the external diameter of the thread is equal to the diameter of the blank portion of the bolt, substantially as described.

2. In a screw-swaging machine, the pair of dies described, having a reducing portion to reduce the diameter of that part of the blank which is to receive the thread, combined with 9 a threading portion, having the threadinggrooves thereon partly sunk below and partly raised above the rear surface of the reducing portion, and also with pointing-dies for the purpose of forming a pointed bolt in which the external diameter of the thread is equal to the diameter of the blank portion of the bolt, substantially as described.

3. In a screw-swaging machine, the pair of dies described, having a threading portion, a reducing portion, and a pointing portion in combination, said pointing portion extending the entire length of the threading and reducing portions, or nearly so, substantially as described.

4. In a screw-swaging machine, the pair of dies described, having threading portions, with grooves cut in their respective faces, combined with pointing portions sloping from the front to the rear of the threading portion to allow for the lengthening of the bolt during the process of swaging the thread thereon, substantially as described.

5. In a screw-swaging machine, a pair of threading-dies having right-angulargrooves cut in a portion of their respective faces, combined with pointing portions sloping from the 

